values

type Array interface {
	Value
	Get(i int) Value
	Set(i int, v Value)
	Append(v Value)
	Len() int
	Range(func(i int, v Value))
	Sort(func(i, j Value) bool)
}

type BinaryFuncSignature struct {
	Operator    ast.OperatorKind
	Left, Right semantic.Nature
}

type BinaryFunction func(l, r Value) (Value, error)

type Duration int64

type Function interface {
	Value
	HasSideEffect() bool
	Call(args Object) (Value, error)
}

type Object interface {
	Value
	Get(name string) (Value, bool)
	Set(name string, v Value)
	Len() int
	Range(func(name string, v Value))
}

type Scope interface {
	// Lookup a name in the scope
	Lookup(name string) (Value, bool)

	// LocalLookup a name in current scope only
	LocalLookup(name string) (Value, bool)

	// Bind a variable in the current scope
	Set(name string, v Value)

	// Create a new scope by nesting the current scope
	// If the passed in object is not nil, its values will be added to the new nested scope.
	Nest(Object) Scope

	// Return the parent of the current scope
	Pop() Scope

	// Number of visible names in scope
	Size() int

	// Range over all variable bindings in scope applying f
	Range(f func(k string, v Value))

	// Range over all variable bindings only in the current scope
	LocalRange(f func(k string, v Value))

	// Set the return value of the scope
	SetReturn(Value)

	// Retrieve the return values of the scope
	Return() Value

	// Create a copy of the scope
	Copy() Scope
}

type Time int64

type Typer interface {
	Type() semantic.Type
	PolyType() semantic.PolyType
}

type Value interface {
	Typer
	IsNull() bool
	Str() string
	Bytes() []byte
	Int() int64
	UInt() uint64
	Float() float64
	Bool() bool
	Time() Time
	Duration() Duration
	Regexp() *regexp.Regexp
	Array() Array
	Object() Object
	Function() Function
	Equal(Value) bool
}

type ValueStringer interface {
	String() string
}